[Formulajones]

I would say yes to that. Larger displacement and/or more HP would create more heat. From my experience it's marginal.
I just pulled the 454 out of my chevelle for a 598. The 454 made 608hp. That engine was in the car for 25 years. It always ran very cool. As long as ambient temps were in the 80's or less that thing rarely got over 158 degrees with slow driving around town, highway I'd see 164-165. On the hottest days over 100 degrees 172-174 was as hot as I saw the engine get. That engine just never would get hot.
The 598 making 786hp, changing nothing else, driving those same slow speeds it's pretty much locks in and settles at 162 degrees. On the highway it's 174-175. Driving it when the temps were over 100 degrees the hottest the engine got was 182 on the highway but even when it's 105+ outside it cools back down to the 170's as soon as I'm off the highway and driving slower back roads. So it does run a few degrees warmer than the 454 did but it's nothing alarming. Both engines are iron blocks with aluminum heads.

The cooling system is the stock 7 blade clutch fan, stock chevelle big block fan shroud, and a Griffin 2 row radiator with 1.5" tubes. Nothing fancy at all.